SLR - September 2015 - Pegah Samouhi

Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial

Reference: Beyer R, Kongsgaard M, Hougs Kjær B, Øhlenschlæger T, Kjær M, Magnusson SP. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial. Am J Sports Med. 2015 Jul; 43(7): 1704-1711

Scientific Literature Review

Reviewed By: Pegah Samouhi, DPM
Residency: Cedars-Sinai Medical Center, Los Angeles

Podiatric Relevance: The prevalence of Achilles tendinopathy is estimated to be as high at 30-50 percent of all sports injury. Although the exact cause of Achilles tendinopathy remains unknown, the histopathology and gene expression data indicates chronic tendinopathy is not an inflammatory condition but rather a failed healing process that causes degenerative changes of the hierarchical tendon structure, neovascularization, and nerve ingrowth. As podiatric physicians we are faced with many patients, especially athletes (avid runners), who present with midsubstance Achilles tendonitis and for decades it has been standard to treat with eccentric training (ECC) although there is no convincing evidence that it is the most effective exercise regimen. It has been shown that about 45 percent of patients do not respond to ECC exercises. This study’s purpose is to evaluate the effectiveness of heavy slow resistance training (HSR) vs ECC among patients with midportion Achilles tendinopathy.

Methods: This is a prospective randomized single blind controlled trial with a 12-week intervention period and a 52 week follow up period. A total of 58 (47 completed study) patients with chronic midsubstance Achilles tendinopathy were included in the study. Diagnosis was made by an experienced sports medicine physician on the basis of defined clinical findings (Victorian Institute of Sports Assessment-Achilles VISA-A), visual analog scale (VAS), physical examination and pain duration of at least three months. In addition, US findings of anterior posterior thickening of the midtendon level with hypoechoic area and a color Doppler signal within the hypoechoic area needed to be present for diagnosis. Patients who received treatment within four weeks were excluded. The ECC group consisted of n=30 (final n=25) and the HSR group consisted of n=28 (final n=22), which were deemed clinically significant.

Success of treatment was measured by improvement on the VISA-A>10 points and the VAS pain scale during five heel rises and during running at 0,12, and 52 weeks. Baseline characteristics where analyzed with unpaired Student t tests. Outcome measures were analyzed using Bonferroni-adjusted post hoc tests. Patient satisfaction was measured at 12 and 52 weeks and activity level at 0,12, and 52 weeks were analyzed using the Fisher exact tests. A Pearson correlation coefficient was employed to examine if changed in color Doppler activity over time was related to changed in VISA-A score over time.  

Results: It was determined that both groups showed improvement on the VISA-A, the VAS and activity level which were maintained at the 52 week follow up. There was a significant difference between patient satisfaction after 12 weeks with HSR (100 percent) than with ECC (80 percent) with a p values of 0.052, but not after the 52 week follow up. No significant difference was noted between the two groups.

Conclusions: Based on the authors’ findings there were no significant differences between the ECC and HSR groups, however both groups showed positive outcomes and improvements. Although there was no significant difference between both groups for most variables measured, there was a significant difference between patient satisfaction scores at 12 weeks follow-up favoring the HSR to the ECC regimen. This is an important finding for practicing physicians because in the realm of clinical compliance, we tend to see patients being more committed to following through with treatment if they are satisfied with the outcomes. Furthermore, this study could have been strengthened if a tendon biopsy was to be performed to examine if and how the interventions influenced the collagen content, crosslink composition and fibril compositions of tendons before and after completion of regimen. This study set out to prove that HSR is a superior mode of non-surgical treatment for midsubstance Achilles tendonitis, as compared to previously practiced ECC. Although their hypothesis was not confirmed, it was found that both modalities provided great outcomes, and this has clinical significance in that now practicing physicians have different modalities to suggest to their patients, without compromising patient care. 

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